Exercise and Type 1: Lessons from a researcher and Person with Diabetes (PWD) Michael C. Riddell, PhD. School of Kinesiology and Health Science, Muscle.

Exercise and Type 1:Lessons from a researcher and Person with Diabetes (PWD)

Michael C. Riddell, PhD. School of Kinesiology and Health Science, Muscle Health Research Centre, Physical Activity and Diabetes Unit, Faculty of Health

Objectives1. Explain briefly why exercise is so

important for our diabetes2. Provide an overview of the

physiology of exercise and diabetes3. Outline some pump and insulin

injection strategies to improve blood sugar control during (and after) exercise

4. Discuss the advantages and limitations of continuous glucose monitoring (CGM) for exercise

• Regular exercise/sports participation is associated with MAJOR health benefits for people with type 1:– Improved mental and physical health (if not sugar control)

– Enjoyment– Neuromuscular and cardiovascular development and fitness– Prevention from diabetes-related complications– Weight maintenance and conditioning– Enhanced insulin sensitivity– Increased independence later in life– Increased life expectancy (10 years)

Exercise, why bother?

Diabetes and exercise

• Common part of children's lives• Encouraged in diabetes• Benefits of exercise include

– Sense of well-being– Weight control– Limit rise in glucose after meals– Lowers heart rate and blood pressure– Lowers blood lipid levels

• Reduces cardio-vascular risk

• Hypoglycaemia

• Hyperglycaemia

• Ketones

BENEFITS RISKS

Exercise is however, a complex variable…

Glucose levels during an active day for an adolescent who does not

have diabetes

Euglycemia

Exercise and Diabetes-101

Have you ever wondered “why is it so darn hard to manage physical activity and type 1 diabetes?”

Why Exercise Management is Challenging

• We do different types of exercise

• We are afraid to develop hypoglycemia

• We all respond to exercise differently

• Even we don’t respond exactly the same way twice!

• We don’t make ANY adjustments for exercise

• The adjustments we are told to make don’t work

• It is impossible to perfectly match the insulin we take to what our bodies need

Exercise, Insulin and Glucose

Person without diabetes Person with diabetes

Insulin release Insulin “levels”

BG levels BG levels

Hyperglycemia and Exercise

Competitive events and/or high intensity exercisecan cause hyperglycemia

Competition

50% correction bolus

Exercise and Diabetes: Advanced

5-7mM

ExerciseInsulinfood

Balanced Blood Sugar

Increased by Decreased byInsulin

food

Blood Glucose Flux During Exercise in T1DM

Glycemic control remains a challenge… Exercise

causes major perturbation to glucose turnover…

• Frequent testing is essential• A pump can help

Physical Activity Levels and HbA1c (Type 1)

N= 296 children, adolescents, and young adults with type 1 diabetes

Galler et al., Diabetes Care 2011

“Diabetes duration, socioeconomic status, and daily media consumption time are significant risk factors for poor glycemic control”

Hours of Exercise/Week

Aerobic Exercise

Aerobic exercise causes two phases of hypoglycemia and may cause post-exercise highs

45 mincycling

1

2

post-exercise rise

Pumpers can have less post-exercise rise than those on needles

Yardley et al., 2012, Diabetes Technology & Therapeutics

Intense exercise causes a rise:The 10-Second Sprint

Fahey et al., JCEM 2012

Subjects with Type 1 Diabetes Non-diabetic subjects

Hypoglycemia

Hyperglycemia

ANAEROBICShort durationHigh-intensity

AEROBICLonger durationLower Intensity

Types of Exercise Weightlifting, Power lifting

Track (sprinting & field events), Diving (Platform & springboard)

American football, Swimming (sprints), Gymnastics, Fencing

Wrestling, Volleyball, Ice hockey, Track cycling

Basketball, Soccer, Tennis, Lacrosse

Speed skating (500-1000m)

Skiing (slalom & downhill), Field hockey

Rowing (middle distance)

Running (middle distance), Speed skating (>1500m)

Road cycling

In-line skating

Cross country skiing

Race walking

Marathon running

Iron Man triathlon

Ultra-marathon running

Resistance Exercise

Resistance exercise may be better than Aerobic exercise for glucose control

Yardley et al., Diabetes Care, 2012

Resistance exercise first protects against hypoglycemia during Aerobic exercise

Yardley et al., Diabetes Care, 2012

Bracken, West and Bain, Pre-exercise Insulin and Carbohydrate Strategies in the Exercising T1DM Individual. In Clinical Management of the Athlete Editor: Ian Gallen.Springer-Verlag, London 2012

Components of good blood glucose management prior to physical activity

MDI adjustments for Aerobic exercise

1. Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity)

2. Lower pre-meal bolus insulin by 25-75% and consider adding 10-15 g CHO at the start of the activity

3. With day-long or unusual activities such as camps, tournaments etc. consider a 30-50% reduction of long-acting insulin the night before and on the day of the activity

Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68

ExCarbswww.yorku.ca/mriddell/

MDI adjustments for Aerobic exercise

1. Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity)

2. Lower pre-meal bolus insulin by 25-75% and consider adding 10-15 g CHO at the start of the activity

3. With day-long or unusual activities such as camps, tournaments etc. consider a 30-50% reduction of long-acting insulin the night before and on the day of the activity

Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68

Duration of exercise Intensity of exercise

30 minutes

60 minutes

Mild 25% 50%

Mod 50%

75%

Heavy 75%

Pump Adjustments for Aerobic Exercise- Temp Basal Adjustments

• Consider reducing basal insulin infusion rates by about 50%, 60-90 minutes before the start of aerobic type exercise that lasts >30 minutes.

• Also consider a temp basal during sleep– 20% reduction in basal insulin rate

overnight

Hypoglycemia management strategies - CSII

1. Suspend/reduce basal insulin by 30-100%, 60-90 minutes BEFORE the start of exercise until the end of the activity• Disconnection/suspension should be

no more than 2 hours

2. Ex carbs- can be much lower if insulin adjustments are made (8-20g/hour)

3. Reduce the mealtime bolus by 25-75%

Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68

Insulin units

Time: 0.00 6.00 12.00 18.00 24.00

Absent basal rate

Basal rate

Hypoglycemia Management Strategies- Summary

1. Ex carbs (~1 gram per kg body mass per hour of exercise) when relative hyperinsulinemia exists

2. Lowering pre-meal bolus insulin (25-75%)3. Suspend/reduce basal insulin (60-90 minutes

BEFORE exercise)4. Prevention using frequent BG testing and

CGM

Exercise with Real-Time CGM

Real-Time Continuous Glucose Monitoring and Small Amounts of Carbohydrate Prevent Hypoglycemia in Active Youth with T1DM

Riddell and Millikin, Diabetes Technology & Therapeutics, 2011

hockey

We find that sports like hockey can increase glucose in early recovery and cause hypoglycemia later at night during sleep... CGM can help identify these issues

Pizza, Choc Milk (53g)50% bolus (MDI)

hockey

Suggestions for post-exercise hyperglycemia

• Resume normal insulin basal rate if on a pump (cancel any temp basal)

• Replace ½ of the missed basal insulin as a correction bolus• Calculate insulin correction bolus and divide by ½ (MDI or

pump)• Correct any hyperglycemia conservatively at the next meal

(MDI or pump)

Real-Time CGM Allows for Proactive Measures

race

1. 8:00AM breakfast (oatmeal, yogurt and fruit)

1 2

2. 10:30 AM basal reduction to 50% for 3 hours

3

3. 11:45 race start-Ex carbs: (~60 grams in total)

4

4. 2:00PM race ends- bolus 2 units immediately- glucose still rose

5

5. 3:00PM ate sandwich, fruit, cookies with full bolus

6

6. 5:30PM correction bolus

7

7. 7:00 PM dinner, full bolus

CGM Pros and Cons• Pros: Sensor-augmented pump capacity (auto shut

off), sense of “security”, do not need to stop and poke, can be informative for future titrations in insulin and or carb (Carelink data), helps to identify the areas for improvement, can allow for being proactive/preventative (enhancing stability)

• Cons: Slight delay in equilibration between plasma and interstitial fluid, must be calibrated properly (inherent to all errors of meters plus own error), expense, comfort, acceptance

Factors affecting glucose response

• Duration of activity• Intensity of activity• Type of activity• Metabolic control• Insulin regimen• Absorption of insulin• Timing and type of food• Stress and competition involved

Managing exercise- key points

• Very variable effects in different children• Monitoring glucose is the key• Know glucose value before activity• Snack before the activity• Interrupt activity every 30 minutes for an

additional snack• Monitor glucose 30-60 minutes after the end

of the activity

Managing exercise- key points (2)

• Treat low glucose with additional rapidly-digested food

• After prolonged activity, additional snack before sleeping, and should have glucose monitored during the night

• Accurate records of activity, food intake and glucose values

Carrie Henderson, RD, CDEMcMasterwww.volumesdirect.com